The hydration of olefins to alcohols in general, and specifically the hydration of butenes to butanols, are commercially important reactions as the alcohol products find several important industrial applications. Hydration reactions are normally acid catalyzed reactions. Because olefins generally have very low solubility in water, relatively strong acids are often required to achieve the desired kinetics for the reaction. The use of strong acids, however, is typically sought to be avoided as the acids can be highly corrosive to the reactor and associated equipment and the processes for acid re-concentration and aqueous waste treatment can be energy demanding.
One preferred technology for hydrations includes the use of thermally stable solid catalysts. Cationic exchange resins and zeolite are important solid catalysts for olefin hydration because it eliminates the use of strong aqueous acids. Cationic exchange resins are known to offer substantial reaction rates in both polar and non-polar media. The use of sulfonated polystyrene resins cross-linked with divinyl benzene as catalysts for the hydration of olefins, such as propylene or butene, has been generally described in the literature (see e.g., U.S. Pat. No. 4,579,984 and U.S. Pat. No. 2,477,380; and references cited therein). While the cationic exchange resins offer several desired advantages, such as ease in separation, and providing non-corrosive environment, the corresponding conversion rates are low. The corresponding olefin rate with solid catalyst (such as the cationic exchange resin) is quite low, typically reported as less than 10% olefin converted by a single pass. Therefore, the need exists to develop a new solid catalyst process that overcomes the equilibrium limitations described above and provides a significantly increased olefin conversion.